Simplify packageToolbox by using ToolboxOptions

[michellehirsch]

packageToolbox looks more complicated than it needs to be. Use ToolboxOptions to specify the location of the released MLTBX instead of trying to find it and move it:

opts = matlab.addons.toolbox.ToolboxOptions(tbxPackagingProjectFile);

% Change output file location to release folder, but keep output file name.
[~,filename] = fileparts(opts.OutputFile);
opts.OutputFile = fullfile(pwd,"release",filename+".mltbx");

matlab.addons.toolbox.packageToolbox(opts);